2-27

• 0:13:08: Q1 what is O O^T if O is orthogonal? ANS: I

• 0:36:56: Q2, what is S inverse? ANS: \(\begin{pmatrix}1/s&0\\0&1/s\end{pmatrix}\)

• 0:41:28: Q3. what is R^{-1}? ANS: \(\begin{pmatrix}\cos(\theta)&\sin(\theta)\\-\sin(\theta)&\cos(\theta)\end{pmatrix}\)

• 0:46:34: Q4. what is the T for mirror across line y = x? ANS: \(\begin{pmatrix}0&1\\1&0\end{pmatrix}\)

• 0:49:01: Q5 can we representation translation with a 2x2 matrix as well? ANS: No

• 1:06:23: Q6 is this transformation affine? ANS: No